Tim Jost of Lexington, Va., wrote: "The Post gives equal coverage to both the anti- and pro-war rallies. Were the rallies roughly equal in size? All other news sources I have read on the march note that the antiwar rally was much larger."

The Post's story last Sunday on Page A8 by Metro reporters Michelle Boorstein, V. Dion Haynes and Allison Klein was by and large straightforward and accurate, but there was a hole in it you could drive a Mack truck through.

The story did not say that the antiwar protest was exponentially larger than the pro-war demonstration. The headline and photo display exacerbated the problem.

Covering protests on deadline is an unenviable assignment; so is combining photos and the work of several reporters into a coherent package. An editing mistake led to the omission. Boorstein, who wrote the story, said, "The fact that the antiwar crowd was much larger and an estimate of the war-supporter crowd were initially in the story -- and high up. However, news (from the 'die-in' and arrests) was breaking on deadline and beyond, and we were busily reorganizing the entire story several times under a time crunch."

Assistant City Editor Joe Davidson handled the story. "We were editing in takes [the story was moving in installments] with info being shifted between takes. In the process, the reference to numbers essentially fell through the cracks between the takes." Metro Editor R.B. Brenner, who supervised coverage, said, "We should have mentioned that the pro-war group was much smaller. It was an oversight."

The headline read: "Dueling Demonstrations." The subhead read: "As Thousands March to the Capitol to Protest Iraq Conflict, 189 Arrested; War Supporters Take on 'Vocal Minority.' " Absent an explanation, a reader might think that the war supporters were in the majority.

A clarification on Tuesday said the headline "may have given an incorrect impression about the number of pro-war and antiwar protesters. War opponents significantly outnumbered war supporters." The clarification should have been a correction and should have referred to the omission in the story as well.

Michael Cushman of the District wrote: "The picture selection opens with a large picture of the PRO-war protesters ( Gathering of Eagles) right in the sweet spot at the top center. It was a much larger picture than any showing the antiwar crowd and seemed to inflate the importance of the pro-war support."

Cushman was right about the inside photos. Three smaller ones were about the arrests of 189 antiwar activists in a "die-in." Another photo showed an antiwar protester and a war supporter.

Nicole Werbeck, Page 1 photo editor, chose the photos, and the News Desk, which designs pages, decided their size and placement. News Editor Vince Bzdek said he could see why the antiwar readers complained. Though there was a small photo of the antiwar march on Page 1,"hindsight tells me the biggest [Page A8] photo should have been of the rally itself."

Cushman and others complained about crowd estimates -- a minefield for reporters, because protest organizers often inflate the numbers."Estimated attendance numbers are given for antiwar [marchers] . . . while NO estimate or count is given for the pro-war group," Cushman wrote.

Police on the Mall are forbidden by law to give official crowd estimates. Reporters said the antiwar march permit estimated 10,000 would attend; a police officer gave reporters the same estimate off the record.

Metro columnist Marc Fisher did a believable count -- 6,850 for the antiwar march and 800 for the war supporters' rally. He counted the antiwar marchers from their starting point at Lafayette Park, where they passed through the narrowest point on the parade route, the corner of 15th Street and New York Avenue NW. He estimated the number of people in each line and multiplied that by the number of lines.

"It was one of the easiest and most confident crowd counts I've done in 25 years of crowd counting because the bollards nicely regulated the number filing through at any given moment. The 800 at the pro-war rally were so few that they were easily counted individually," Fisher said. He said a few hundred more people, at most, joined the antiwar protest at the Capitol, a number that sounded right to reporter Klein, who was there.

That estimate wasn't in the story or in Fisher's column, only in his blog. Brenner didn't feel comfortable with using it "because there was no way to know how many people joined the protest at the Capitol."

Fisher's numbers, with an explanation of his methods, along with a count by Klein at the Capitol, would have added credible estimates to the story.

Crowd estimates are a perennial problem. Future stories about large demonstrations should have a "how many" box using the permit estimate, any off-the-record estimates, and estimates by veteran reporters and editors.